First of all I would like to thank you for your observation, you are absolutely correct, it was a typo mistake from our side and it will be fixed (within 30 minutes) in the lesson attachments. The Event No. 10 & Event No. 11 in the Influence Schedule was exchanged.
Regarding your first question about using Window Analysis Technique, the window intervals should be updated as agreed in sequence. It means if your window interval is one month, you need to include the update even if you do not have any events in that duration. This is because windows analysis takes into consideration contractor delays. Accordingly, the client could ask for all time intervals to assure that there were no delays by contractor at this stage.
Regarding question no.2, as I explained to you above, using the window analysis is connected to updating your schedule within an agreed time interval, this time interval by the way could be more or less than one month depending on the project conditions such as the whole project time or activities trend, however applying window analysis when only you have an event you want to explain will not give you the accurate result required.
Please don’t hesitate to contact me if you have any questions.